John Robertson wrote:
On 2017/08/26 7:52 PM, Dave M wrote:
John Robertson wrote:
I am replacing an old TRIAC that is used for a solenoid driver
driven by a photo-flash (I have dozens of these in my classic rifle
gallery) and I can't find anything on line about this particular
device. I know it is 400V, 3A, and is in a TO-11 like metal can however
what I can't find is the Gate current. This is a sensitive gate
TRIAC and I suspect it is either a 3MA or a 10MA device, but would
like a copy of the original TECCOR specs to be sure that the
replacement I am using is close enough to the original for long
term reliability. This is being controlled by a device called a
Vactrol - VTL2C3, and I have several dozen of these controllers
that eventually need upgrading. So, if anyone has a TECCOR Electronics
Inc. manual lying around from
the early 70s and can scan me the page(s) on the Q4003M3 that would
be great. I have found sheets online for other flavours of the Q4003
series, but just not the Mx version.

Thanks!

John :-#)#


The Teccor triac part numbering scheme says that the "M" is for a
non-isolated TO-218 package. You could just substitute another
package type such as the "F" or "R" package and get the same triac
in a slightly different package.
Looks like the "M" package was discontinued for triacs years ago,

Dave M



Yes, I have tried already a few other sensitive gate TRIACs (2N6073 is
close) in place of this one, but none seem to work the same way even
when they appear to have similar ratings. The TRIAC is controlled by a
LED/Photo-resistor (Vactrol) instead of a LED/Opto DIAC or similar.
Appears to be using Quadrant II control where the Vactrol enables the
TRIAC via a 12K resistor to M1 where M2 is connected to the load. M1
is tied to the power return/neutral (white) side of the 115VAC power.
Here is the PDF circuit:

http://www.flippers.com/pdfs/Vactrol...lled_TRIAC.pdf

I have tried subbing a MOC3020 LED-OptoTriac but that didn't work
reliably. Basically this circuit works by a CDS cell on the input that
reacts to a photoflash strobe in my rifles at the gallery. Problem is
this is 1970s tech and they are gradually failing. Recapping helped,
but now the opto-couplers are breaking down and my transistor theory
is too weak to change this one-shot monostable timer output to trigger
something more up to date in TRIAC drivers.

I just need to sit down and spend a couple of hours on this project.

Thanks,

John :-#)#


Seems like a triggered one-shot 555 timer circuit would be a natural
solution to this problem. Circuit values are easily calculated for the
required delay, and the 555 can drive the triac directly or through an
optocoupler.

What's the normal ON time for the existing circuit? Do you use only the
photocell input or in conjunction with the reed switch input?

Dave M